The growth patterns of individuals in populations under adverse environmental conditions do not resemble the patterns described for industrial populations, particularly regarding the differential performance of each sex. In the current literature females are generally thought to be less responsive to environmental insult, males more so. Previous research with a homogeneous East Indian community in southern Trinidad has led to the definition of secular increase in the height of the adult men, the absence of such increase in the height of adult women, differential morbidity and mortality of infants by sex, differential parent-child height correspondence by sex and other parameters which indicate that this community is presently experiencing rapid alterations in the growth performance of children as a result of significant environmental and economic betterment in the last two decades. The present proposal is to locate and re-examine the stature and related characteristics of a sample of 197 children who were first examined in 1968-69, and are representative of all births in the community between 1966 and 1968. The data obtained will permit a fuller analysis of the differential experience of each sex during this extraordinary transition.